Identifying coverage holes using inter-rat handover measurements

ABSTRACT

Embodiments of systems and techniques for identifying coverage holes in a radio access technology (RAT) are described. In some embodiments, a network management (NM) apparatus may receive a first report, including one or more measurements taken by a first user equipment (UE), in response to an event related to a handover of the first UE between a first radio access technology (RAT) and a second RAT different from the first RAT. The NM apparatus may receive a second report including one or more measurements taken by a second UE in response to an event related to a handover of the second UE between the first RAT and a third RAT different from the first RAT. The NM apparatus may identify a hole in a coverage area of the first RAT based at least in part on the first and second reports. Other embodiments may be described and claimed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/676,775, entitled “Advanced Wireless Communication Systems andTechniques” and filed Jul. 27, 2012, the contents of which are herebyincorporated by reference in their entirety herein.

TECHNICAL FIELD

The present disclosure relates generally to wireless communication, andmore particularly, to systems and techniques for identifying coverageholes in a radio access technology (RAT).

BACKGROUND

Some RATs, such as evolved universal terrestrial radio access (E-UTRA)technology, may be deployed in locations with dense populations in anattempt to mitigate traffic congestion during peak hours. Because of theselective use of these RATs in high density locations, any such RAT mayhave many coverage holes (e.g., in the low density locations betweenhigh density locations), particularly in the initial deployment phase ofthese RATs. Legacy RATs, such as a universal mobile telecommunicationssystem terrestrial radio access (UTRA) technology or a global system formobile communications enhanced data rates for global system for mobilecommunication evolution radio access (GERA) technology, may providecoverage to the underlying area (in both high and low densitylocations). In an area with multiple RATs, user equipment (UE) thatutilizes services provided by the RATs may be handed off between RATs(referred to as an inter-RAT handover) in response to, for example,movement of the UE and changes in RAT traffic.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings. To facilitatethis description, like reference numerals designate like structuralelements. Embodiments are illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings.

FIG. 1 illustrates an environment in which two inter-RAT handovers occurproximate to a coverage hole in one RAT, in accordance with variousembodiments.

FIG. 2 is a block diagram illustrating an example system for RATcoverage analysis and corrective action, in accordance with variousembodiments.

FIG. 3 is a flow diagram of an example inter-RAT handover processexecutable by a network management (NM) apparatus, in accordance withvarious embodiments.

FIG. 4 is a flow diagram of an example inter-RAT handover processexecutable by an evolved nodeB (eNB), in accordance with variousembodiments.

FIG. 5 is a flow diagram of an example inter-RAT handover processexecutable by a user equipment (UE), in accordance with variousembodiments.

FIG. 6 is a block diagram of an example computing device suitable forpracticing the disclosed embodiments, in accordance with variousembodiments.

DETAILED DESCRIPTION

Embodiments of systems and techniques for identifying coverage holes ina radio access technology (RAT) using inter-RAT handover measurementsare described. In some embodiments, a network management (NM) apparatusmay receive a first report, including one or more measurements taken bya first user equipment (UE), in response to an event related to ahandover of the first UE between a first radio access technology (RAT)and a second RAT different from the first RAT. The NM apparatus mayreceive a second report including one or more measurements taken by asecond UE in response to an event related to a handover of the second UEbetween the first RAT and a third RAT different from the first RAT. TheNM apparatus may identify a hole in a coverage area of the first RATbased at least in part on the first and second reports.

The systems and techniques disclosed herein may enable the detection andcharacterization of coverage holes that may not be otherwise detected.For example, when a cell of a source RAT such as E-UTRA technology isoverlaid by one or more cells of other RATs (e.g., an UTRAN cell or aGERAN cell), a UE approaching a coverage hole in the E-UTRAN may behanded over to one of the other RATs instead of generating a radio linkfailure (RLF) report. Because no RLF report is received by the E-UTRAN,network management functions may be unaware of the E-UTRAN coveragehole. By transmitting measurement reports when a handover to another RAToccurs, in accordance with some of the embodiments disclosed herein, asource RAT (such as an E-UTRA technology) may identify previouslyunnoticed coverage holes.

Various embodiments of the systems and techniques described herein maybe advantageously used in a number of applications to increase thequality of RAT services. For example, coverage holes identified usinginter-RAT handover measurements may be minimized by adjusting one ormore service parameters of existing RAT cells (e.g., shape or size). Inanother example, identified coverage holes may be eliminated or reducedby deploying new base stations (e.g., eNBs, also referred to as enhancednodeBs and eNodeBs) in coverage-deficient areas. Such embodiments may beincluded in coverage and capacity optimization (CCO) operations. Thepresent disclosure may be particularly advantageous in self-organizingnetwork (SON) applications, including those in which networkoptimization is centralized in one or more NM apparatuses or otherdevices.

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown by way ofillustration embodiments that may be practiced. It is to be understoodthat other embodiments may be utilized and structural or logical changesmay be made without departing from the scope of the present disclosure.Therefore, the following detailed description is not to be taken in alimiting sense, and the scope of embodiments is defined by the appendedclaims and their equivalents.

Various operations may be described as multiple discrete actions oroperations in turn, in a manner that is most helpful in understandingthe claimed subject matter. However, the order of description should notbe construed as to imply that these operations are necessarily orderdependent. In particular, these operations may not be performed in theorder of presentation. Operations described may be performed in adifferent order than the described embodiment. Various additionaloperations may be performed and/or described operations may be omittedin additional embodiments.

For the purposes of the present disclosure, the phrases “A and/or B” and“A or B” mean (A), (B), or (A and B). For the purposes of the presentdisclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B),(A and C), (B and C), or (A, B and C).

The description may use the phrases “in an embodiment,” or “inembodiments,” which may each refer to one or more of the same ordifferent embodiments. Furthermore, the terms “comprising,” “including,”“having,” and the like, as used with respect to embodiments of thepresent disclosure, are synonymous.

As may be used herein, the term “module” or “circuitry” may refer to, bepart of, or include an Application Specific Integrated Circuit (ASIC),an electronic circuit, a processor (shared, dedicated, or group) and/ormemory (shared, dedicated, or group) that execute one or more softwareor firmware programs, a combinational logic circuit, and/or othersuitable components that provide the described functionality.

Referring now to FIG. 1, an environment 100 is illustrated in which twointer-RAT handovers occur proximate to a coverage hole 106 in a firstRAT, in accordance with various embodiments. In FIG. 1, the first RAT(indicated as RAT 1) may be supported by two base stations 102 a and 102b. Each base station 102 a and 102 b may provide service in a respectivecoverage cell 104 a and 104 b. In some embodiments, the first RAT may bean E-UTRA technology, and base stations 102 a and 102 b may be (or mayinclude) eNBs. A second RAT (indicated as RAT 2) may be supported by abase station 108 that provides service in a coverage cell 110. A thirdRAT (indicated as RAT 3) may be supported by a base station 112 thatprovides service in a coverage cell 114. In some embodiments, the secondand third RATs may be different RATs (e.g., an UTRA technology and aGERA technology). In some embodiments, one or both of the second andthird RATs are different RATs than the first RAT. The coverage cells 104a, 104 b, 110 and 114 may overlap in any of a number of combinations.

In some embodiments, the first RAT may have a coverage hole, generallyindicated as 106, representative of an area of deficient service underthe first RAT. Deficient service may include, for example, failure toachieve a desired level of signal strength or failure to successfullyprovide service to UE devices within a certain number of access attempts(e.g., radio resource control (RRC) connection attempts and/or randomaccess attempts). Coverage hole 106 may be the result of the geographicseparation of base stations 102 a and 102 b, obstructions (such asbuildings) between base stations 102 a and 102 b, or any of a number ofother conditions resulting in a gap between coverage cells 104 a and 104b. When a UE travels to the right along line 116 from RAT 1 coveragecell 104 a, the UE may experience insufficient RAT 1 service as itapproaches coverage hole 106. Such a circumstance is represented insignal strength diagram 122, which illustrates that the strength of theRAT 1 signal at location 118 (proximate to coverage hole 106) may be toolow to support adequate RAT 1 service. In some embodiments, the UE maybe handed over to RAT 2 (supported by base station 108) when the UE isproximate to location 118. This inter-RAT handover may occur when thestrength of the RAT 2 signal exceeds a relative or absolute thresholdabove the strength of the RAT 1 signal, for example.

Similarly, when a UE travels to the left along line 116 from RAT 1coverage cell 104 b, the UE may experience insufficient RAT 1 service asit approaches coverage hole 106. Signal strength diagram 122 illustratesthat the strength of the RAT 1 signal at location 120 (proximate tocoverage hole 106) may be too low to support adequate RAT 1 service. Insome embodiments, the UE may be handed over to RAT 3 (supported by basestation 112) when the UE is proximate to location 120. This inter-RAThandover may occur when the strength of the RAT 3 signal exceeds arelative or absolute threshold above the strength of the RAT 1 signal,for example.

In some embodiments, measurements taken in response to events related tointer-RAT handovers (such as the handover from RAT 1 to RAT 2 proximateto location 118 and the handover from RAT 1 to RAT 3 proximate tolocation 120) may be used to identify coverage holes (such as coveragehole 106). For example, a network management (NM) apparatus may receivemultiple reports (e.g., from one or more eNBs) including measurementstaken by UEs in response to inter-RAT handover events, and may identifya hole in a coverage area (e.g., the hole's location and size) based atleast in part on the reports. Additional embodiments are describedherein.

Referring now to FIG. 2, a block diagram of an example system 200 forRAT coverage analysis and corrective action is illustrated, inaccordance with various embodiments. System 200 may be configured tosupport a RAT, such as E-UTRAN. In some embodiments, the RAT supportedby system 200 may be the first RAT (RAT 1) of environment 100 of FIG. 1.Examples of components of system 200 may often be discussed withreference to a 3GPP LTE-A RAT, but system 200 may be used to implementother RATs (such as those discussed herein). System 200 may beconfigured to deliver any of a number of services, such as multimediadelivery over HTTP, live streaming over RTP, conversational services(e.g., video conferencing), and TV broadcasting, for example. System 200may include other wireless personal area network (WPAN), wireless localarea network (WLAN), wireless metropolitan area network (WMAN), and/orwireless wide area network (WWAN) devices such as network interfacedevices and peripherals (e.g., network interface cards (NICs)), accesspoints (APs), redistribution points, end points, gateways, bridges,hubs, etc. to implement a cellular telephone system, a satellite system,a personal communication system (PCS), a two-way radio system, a one-waypager system, a two-way pager system, a personal computer (PC) system, apersonal data assistant (PDA) system, a personal computing accessory(PCA) system, and/or any other suitable communication system. Whileembodiments may be described in the context of LTE-A networks,embodiments may also be employed in other networks (e.g., WiMAXnetworks).

System 200 may include an NM apparatus 202. In some embodiments, NMapparatus 202 may monitor the components of system 200 and collectmeasurements of its performance. Based on the analysis of thesemeasurements, NM apparatus 202 may identify potential problems andimprovements in the configuration and operation of the components ofsystem 200, and may implement changes to system 200. NM apparatus 202may include receiver circuitry 222, coverage-analysis circuitry 224 andcorrective-action circuitry 226. Receiver circuitry 222 may beconfigured for receiving signals from other devices by wired or wirelessconnections. For example, receiver circuitry 222 may be configured toreceive signals from or transmit signals to an element manager (EM)component of an eNB (such as any of eNBs 208-212), a domain management(DM) apparatus 204 (which may provide management functions for a domainor other portion of system 200), or any other suitably configureddevices. In some embodiments, NM apparatus 202 may communicate with aneNB via a wired connection. In embodiments in which receiver circuitry222 is configured for wireless communications, it may include, forexample, one or more directional or omni-directional antennas (notshown) such as dipole antennas, monopole antennas, patch antennas, loopantennas, microstrip antennas, and/or other types of antennas suitablefor reception of radio frequency (RF) or other wireless communicationsignals.

In some embodiments, receiver circuitry 222 may be configured to receivea first report, including one or more measurements taken by a first UE,in response to an event related to a handover of the first UE between afirst RAT and a second RAT different from the first RAT. The eventrelated to the handover may be the issuance of a handover command, thereceipt of a handover command, the presence of a handover condition(such as sufficiently favorable signal strength offered to a UE by adifferent RAT), or any other handover-related event. The RAT supportedby system 200 may be the first RAT or the second RAT involved in thehandover of the first UE.

The first report may include any of a number of measurements taken bythe first UE, such as one or more of a reference signal received power(RSRP), a reference signal received quality (RSRQ), an identifier of acell that served the first UE in the first RAT, location information(e.g., information about the location of the UE when a handover commandis received at the UE), and a time stamp representative of a time of theevent related to a handover (e.g., a time stamp of the time of inter-RAThandover).

In some embodiments, receiver circuitry 222 may be configured to receivea second report including one or more measurements taken by a second UEin response to an event related to a handover of the second UE betweenthe first RAT and a third RAT different from the first RAT. For example,system 200 may support an E-UTRA technology. In some such embodiments,the handover of the first UE may occur between a first E-UTRAN cell andthe second RAT, and the handover of the second UE may occur between asecond E-UTRAN cell and the third RAT. In some embodiments, the secondE-UTRAN cell may be different from the first E-UTRAN cell. In someembodiments, each of the second and third RATs is an UTRA technology ora GERA technology. In some embodiments, the first UE and the second UEmay be a common UE (e.g., one that undergoes multiple inter-RAThandovers).

In some embodiments, one or more of the first and second reports may betransmitted to NM apparatus 202 by an eNB, such as any of eNBs 208-212.In some such embodiments, an element manager embedded in or associatedwith the eNB may transmit one or more of the first and second reports toNM apparatus 202. In some embodiments, one or more reports may betransmitted to NM apparatus 202 by a domain management (DM) apparatus204 in communication with one or more eNBs (such as eNBs 208 and 210, asshown). In some embodiments, one or more reports may be transmitted toNM apparatus 202 by a trace collection entity (TCE) 206 in communicationwith a DM apparatus (such as DM apparatus 204) and/or one or more eNBs(such as eNB 208, as shown).

As discussed above, NM apparatus 202 may include coverage-analysiscircuitry 224 and corrective-action circuitry 226. In some embodiments,coverage-analysis circuitry 224 and corrective-action circuitry 226 maybe included in a centralized coverage and capacity optimization (CCO)function 242 of NM apparatus 202. Coverage-analysis circuitry 224 may beconfigured to identify a hole in a coverage area of the RAT supported bysystem 200 based at least in part on reports associated with handoverevents, such as the first and second reports discussed above. Forexample, in some embodiments, coverage-analysis circuitry 224 mayidentify a hole in a coverage area of the RAT by correlating multiplereports (e.g., the first and second reports). Correlating multiplereports may include, among other things, associating the multiplereports with a same user-session occurrence or a same geographic area.

Corrective-action circuitry 226 may be configured to recommend acorrective action based on the coverage hole identified bycoverage-analysis circuitry 224. In some embodiments, a command toimplement the corrective action may be transmitted to one or morecomponents of system 200, such as one or more of eNBs 208-212 or UEs214-220. In some embodiments, coverage-analysis circuitry 224 and/orcorrective-action circuitry 226 may include a display or other outputconfigured to provide coverage information or corrective actionrecommendations to a human operator, who can then interveneappropriately.

System 200 may include one or more eNBs, such as eNBs 208-212. Each ofeNBs 208-212 may include a number of components; for ease ofillustration, only the components of eNB 208 are shown in FIG. 2. eNBsother than eNB 208 may have similar components. The components of eNB208, discussed in detail below, may be included in one or more of basestations 102 a, 102 b, 108 and 112 of FIG. 1.

As shown, eNB 208 may include first transmitter circuitry 228. Firsttransmitter circuitry 228 may be configured for transmitting wirelesssignals to other devices. For example, first transmitter circuitry 228may be configured to transmit wireless signals to UE 214 or otherdevices suitably configured for wireless communications. Firsttransmitter circuitry 228 may include, for example, one or moredirectional or omni-directional antennas (not shown), as discussedabove. In some embodiments, first transmitter circuitry 228 may beconfigured to transmit, to a UE in a cell served by the eNB (such as UE214, as shown), a command to handover the UE to a RAT that is differentfrom the RAT supported by eNB 208 via system 200. For example, the RATsupported by eNB 208 may be E-UTRA technology, and the different RAT maybe UTRA technology or GERA technology.

eNB 208 may include receiver circuitry 230. Receiver circuitry 230 maybe configured for receiving signals from other devices via wired orwireless connections. For example, receiver circuitry 230 may beconfigured to receive signals from NM apparatus 202, DM apparatus 204,TCE 206, UE 214 or other devices suitably configured. Receiver circuitry230, if configured to receive wireless signals, may include, forexample, one or more directional or omni-directional antennas (notshown), as discussed above. In some embodiments, receiver circuitry 230of eNB 208 may be configured to receive, from the UE in response to thehandover command, one or more measurements taken by the UE andrepresentative of conditions proximate to an edge of the cell served byeNB 208. In some embodiments, the one or more measurements may be takenby the UE in response to receiving the command at the UE. In someembodiments, the one or more measurements may be taken by the UE priorto receiving the command at the UE.

In some embodiments, first transmitter circuitry 228 (discussed above)may be configured to transmit, to the UE, parameters representative ofwhich measurements are to be taken by the UE as representative ofconditions proximate to the edge of the cell. For example, theparameters may be representative of one or more of RSRP, RSRQ, anidentifier of the cell, location information, and a time stamprepresentative of a time of the event related to the handover. In someembodiments, the parameters may be selected by an eNB (such as eNB 208),by a DM apparatus (such as DM apparatus 204), by an NM apparatus (suchas NM apparatus 202), by another component of system 200, or by acombination of components.

In some embodiments, first transmitter circuitry 228 may be configuredto transmit a trigger signal to a UE trigger the reporting ofmeasurements from the UE. The trigger signal may be included with orseparate from parameters representative of which measurements are to betaken by the UE, as discussed above.

eNB 208 may include second transmitter circuitry 232. Second transmittercircuitry 232 may be configured for transmitting signals to otherdevices via wired or wireless connections. For example, secondtransmitter circuitry 232 may be configured to transmit signals to NMapparatus 202, DM apparatus 204, TCE 206, or other devices suitablyconfigured. Second transmitter circuitry 228, if configured to transmitwireless signals, may include, for example, one or more directional oromni-directional antennas (not shown), as discussed above. In someembodiments, second transmitter circuitry 232 may be configured totransmit, to a DM apparatus (such as DM apparatus 204) or an NMapparatus (such as NM apparatus 202), a report including the one or moremeasurements from the UE. The report may be used by the DM apparatus orthe NM apparatus to identify coverage holes in the RAT supported bysystem 200. In some embodiments, the report is transmitted to a CCOfunction of an NM apparatus.

System 200 may include one or more UEs, such as UEs 214-220. One or moreof UEs 214-220 may include any of a number of wireless electronicdevices such as a desktop computer, a laptop computer, a handheldcomputer, a tablet computer, a cellular telephone, a pager, an audioand/or video player (e.g., an MP3 player or a DVD player), a gamingdevice, a video camera, a digital camera, a navigation device (e.g., aGPS device), a wireless peripheral (e.g., a printer, a scanner, aheadset, a keyboard, a mouse, etc.), a medical device (e.g., a heartrate monitor, a blood pressure monitor, etc.), and/or other suitablefixed, portable, or mobile electronic devices. In some embodiments, oneor more of UEs 214-220 may be a mobile wireless device, such as a PDA,cellular telephone, tablet computer or laptop computer. Each of UEs214-220 may include a number of components; for ease of illustration,only the components of UE 214 are shown in FIG. 2. UEs other than UE 214may have similar components.

As shown, UE 214 may include receiver circuitry 234. Receiver circuitry234 may be configured for receiving wireless signals from other devices.For example, receiver circuitry 234 may be configured to receivewireless signals eNB 208 or other devices suitably configured forwireless communications. Receiver circuitry 234 may include, forexample, one or more directional or omni-directional antennas (notshown), as discussed above. In some embodiments, receiver circuitry 234may be configured to receive a command, from an eNB serving the UE (suchas eNB 208) to handover UE 214 to a RAT different from the RAT supportedby system 200. In some embodiments, the different RAT may be an UTRAtechnology or a GERA technology, for example. In some embodiments, theRAT supported by system 200 (e.g., an E-UTRA technology) may have acoverage hole proximate UE 214 when the command is received. In someembodiments, receiver circuitry 234 may receive the command to handoverUE 214 to a different RAT when UE 214 is proximate to an edge of a cellserved by the eNB. In some embodiments, receiver circuitry 234 mayreceive the command to handover UE 214 to a different RAT when UE 214 isproximate to an edge of an E-UTRAN cell served by the eNB and no otherE-UTRAN cell is sufficiently close to the UE to serve the UE.

UE 214 may include transmitter circuitry 236. Transmitter circuitry 236may be configured for transmitting wireless signals to other devices.For example, transmitter circuitry 236 may be configured to transmitwireless signals to eNB 208 or other devices suitably configured forwireless communications. Transmitter circuitry 236 may include, forexample, one or more directional or omni-directional antennas (notshown), as discussed above. In some embodiments, transmitter circuitry236 may be configured to transmit one or more measurements taken by UE214 to eNB 208 or another component of system 200. The measurements maybe representative of conditions proximate to the coverage hole. In someembodiments, transmitter circuitry 236 may transmit the measurements inresponse to receiving a handover command. In some embodiments,transmitter circuitry 236 may transmit the one or more measurements upondetection of a trigger signal. The trigger signal may be transmittedfrom an eNB (such as eNB 208) or some other component of system 200, ormay be transmitted and received internal to UE 214. The trigger signalmay be associated with a handover command (e.g., indicating receipt of ahandover command or successful completion of a handover).

UE 214 may include handover circuitry 238. Handover circuitry 238 may beconfigured to perform (or assist in the performance of) the handover ofUE 214 to the different RAT. For example, handover circuitry 238 may beconfigured to transition UE 214 to the different RAT without aninterruption in service. Handover circuitry 238 may include, forexample, signaling circuitry for sending and receiving request,confirmation, error and security information messages in accordance withvarious handover protocols. In some embodiments, handover circuitry 238may perform the handover after the one or more measurements aretransmitted (e.g., by transmitter circuitry 236) to eNB 208 or anothercomponent of system 200.

UE 214 may include measurement circuitry 240. Measurement circuitry 240may be configured to take the one or more measurements discussed abovewith reference to transmitter circuitry 236. In particular, in someembodiments, the one or more measurements may include an RSRP, an RSRQ,an identifier of a cell that served the UE in the RAT supported bysystem 200, location information, and a time stamp representative of atime of an event related to the handover (such as receipt of thehandover command).

Referring now to FIG. 3, a flow diagram of example inter-RAT handoverprocess 300 executable by an NM apparatus (such as NM apparatus 202 ofFIG. 2) is illustrated, in accordance with various embodiments. It maybe recognized that, while the operations of process 300 (and the otherprocesses described herein) are arranged in a particular order andillustrated once each, in various embodiments, one or more of theoperations may be repeated, omitted or performed out of order. Forillustrative purposes, operations of process 300 may be described asperformed by NM apparatus 202 (FIG. 2), but process 300 may be performedby any suitably configured device.

Process 300 may begin at operation 302, in which NM apparatus 202 mayreceive a first report, including one or more measurements taken by afirst UE (such as UE 214 of FIG. 2), in response to an event related toa handover of the first UE between a first RAT and a second RATdifferent from the first RAT. In some embodiments, operation 302 may beexecuted by receiver circuitry 222 (FIG. 2). In some embodiments, thefirst RAT may be an E-UTRA technology. In some embodiments, the one ormore measurements included in the first report may include one or moreof an RSRP, an RSRQ, an identifier of a cell that served the first UE inthe first RAT, location information, and a time stamp representative ofa time of the event related to a handover.

At operation 304, NM apparatus 202 may receive a second report includingone or more measurements taken by a second UE in response to an eventrelated to a handover of the second UE between the first RAT and a thirdRAT different from the first RAT. In some embodiments, operation 304 maybe executed by receiver circuitry 222 (FIG. 2). In some embodiments, thefirst and second UEs may be a common UE. In some embodiments, each ofthe second and third RATs may be an UTRA technology or a GERAtechnology. In some embodiments, the handover of the first UE betweenthe first RAT and the second RAT (discussed above with reference tooperation 302) may be a handover of the first UE between a first E-UTRANcell and the second RAT, and the handover of the second UE between thefirst RAT and the third RAT may be a handover of the second UE between asecond E-UTRAN cell and the third RAT. The second E-UTRAN cell may bedifferent from the first E-UTRAN cell.

At operation 306, NM apparatus 202 may identify a hole in a coveragearea of the first RAT based at least in part on the first and secondreports (received at operations 302 and 304, respectively). In someembodiments, operation 306 may be executed by coverage-analysiscircuitry 224 (FIG. 2). In some embodiments, operation 306 may includecorrelating the first and second reports. At operation 308, NM apparatus202 may recommend a corrective action based on the identified hole. Insome embodiments, operation 308 may be executed by corrective-actioncircuitry 226 (FIG. 2). Process 300 may then end.

Referring now to FIG. 4, a flow diagram of example inter-RAT handoverprocess 400 executable by an eNB (such as eNB 208 of FIG. 2) isillustrated, in accordance with various embodiments. For illustrativepurposes, operations of process 400 may be described as performed by eNB208 (FIG. 2), but process 400 may be performed by any suitablyconfigured device. eNB 208 will also be described as supporting a firstRAT (e.g., E-UTRA technology).

Process 400 may begin at operation 402, in which eNB 208 may transmit,to a UE in a cell served by eNB 208, a command to handover the UE to asecond RAT that is different from the first RAT. In some embodiments,operation 402 may be executed by first transmitter circuitry 228 (FIG.2). In some embodiments, the second RAT is a UTRA technology or a GERAtechnology.

At operation 404, eNB 208 may transmit, to the UE, parametersrepresentative of which measurements are to be taken by the UE asrepresentative of conditions proximate to the edge of the cell. In someembodiments, operation 404 may be executed by first transmittercircuitry 228 (FIG. 2). The parameters may be representative of an RSRP,an RSRQ, an identifier of the cell, location information, and a timestamp representative of a time of an event related to a handover, forexample.

At operation 406, eNB 208 may receive, from the UE in response to thecommand of operation 204, one or more measurements taken by the UE andrepresentative of conditions proximate to an edge of the cell. In someembodiments, operation 406 may be executed by receiver circuitry 230(FIG. 2). In some embodiments, the one or more measurements may be takenby the UE in response to receiving the command (of operation 204) at theUE. In some embodiments, the one or more measurements may be taken bythe UE prior to receiving the command (of operation 204) at the UE.

At operation 408, eNB 208 may transmit, to a DM apparatus or an NMapparatus, a report including the one or more measurements for use inidentifying coverage holes in the first RAT. In some embodiments,operation 408 may be executed by second transmitter circuitry 222 (FIG.2). In some embodiments, the report transmitted at operation 408 may betransmitted to a CCO function of an NM apparatus.

Referring now to FIG. 5, a flow diagram of example inter-RAT handoverprocess 500 executable by a UE (such as UE 214 of FIG. 2) isillustrated, in accordance with various embodiments. For illustrativepurposes, operations of process 500 may be described as performed by UE214 (FIG. 2), but process 500 may be performed by any suitablyconfigured device.

Process 500 may begin at operation 502, in which UE 214 may receive acommand from an eNB serving UE 214 (e.g., eNB 208 of FIG. 2), the eNBassociated with a first RAT having a coverage hole proximate UE 214, tohandover UE 214 to a second RAT different from the first RAT. In someembodiments, operation 502 may be executed by receiver circuitry 234(FIG. 2). In some embodiments, the second RAT may be an UTRA technologyor a GERA technology. In some embodiments, receiving a command tohandover UE 214 to a second RAT at operation 502 may occur when UE 514is proximate to an edge of a cell of the first RAT served by the eNB(e.g., eNB 208). For example, in some embodiments, receiving a commandto handover UE 214 to a second RAT at operation 502 may occur when UE2214 is proximate to an edge of an E-UTRAN cell served by the eNB and noother E-UTRAN cell is sufficiently close to UE 214 to serve UE 214.

At operation 504, UE 214 may take one or more measurementsrepresentative of conditions proximate to the coverage hole. In someembodiments, the one or more measurements taken at operation 502 mayinclude an RSRP, an RSRQ, an identifier of a cell that served UE 214 inthe first RAT, location information, and/or a time stamp representativeof a time of an event related to the handover. In some embodiments,operation 502 may be performed by measurement circuitry 240 (FIG. 2).

At operation 506, UE 214 may transmit to the eNB, in response toreceiving the command of operation 502, the one or more measurementstaken by the UE. In some embodiments, operation 506 may be performed bytransmitter circuitry 236 (FIG. 2).

At operation 508, UE 214 may perform the handover to the second RAT (perthe command of operation 502). In some embodiments, operation 508 maytake place after one or more measurements are transmitted to the eNB. Insome embodiments, operation 508 may be performed by handover circuitry238 (FIG. 2). Process 500 may then end.

In some embodiments, after the inter-RAT handover of operation 508, UE214 may be configured to log measurements before, during or after aninter-RAT handover, and then transmit these measurements for receipt byNM apparatus 202. Transmission of measurements after inter-RAT handovermay occur in addition to transmission of measurements prior to handover(e.g., per operation 506) or instead of transmission of measurementsprior to handover. In some embodiments, UE 214 may transmit themeasurements, after inter-RAT handover, to a UTRAN or GERAN, which mayforward the measurements to NM apparatus 202. In some embodiments, UE214 may wait to transmit the measurements, after inter-RAT handover,until UE 214 is connected to an E-UTRAN, and may then transmit themeasurements to the E-UTRAN.

FIG. 6 is a block diagram of example computing device 600, which may besuitable for practicing various disclosed embodiments. For example, someor all of the components of computing device 600 may be used in any ofthe NM apparatus (such as NM apparatus 202 of FIG. 2), DM apparatus(such as DM apparatus 204 of FIG. 2, TCEs (such as TCE 206 of FIG. 2),eNBs (such as eNBs 102 a, 102 b, 108 and 112 of FIG. 1 and eNBs 208-212of FIG. 2), or UEs (such as UEs 214-220 of FIG. 2). Computing device 600may include a number of components, including one or more processor(s)604 and at least one communication chip 606. In various embodiments,processor 604 may include a processor core. In various embodiments, atleast one communication chip 606 may also be physically and electricallycoupled to processor 604. In further implementations, communicationchips 606 may be part of processor 604. In various embodiments,computing device 600 may include PCB 602. For these embodiments,processor 604 and communication chip 606 may be disposed thereon. Inalternate embodiments, the various components may be coupled without theemployment of PCB 602. Communication chip 606 may be included in any ofthe receiver and/or transmitter circuitry described herein.

Depending on its applications, computing device 600 may include othercomponents that may or may not be physically and electrically coupled toPCB 602. These other components include, but are not limited to,volatile memory (e.g., dynamic random access memory 608, also referredto as DRAM), non-volatile memory (e.g., read-only memory 610, alsoreferred to as “ROM,” one or more hard disk drives, one or moresolid-state drives, one or more compact disc drives, and/or one or moredigital versatile disc drives), flash memory 612, input/outputcontroller 614, a digital signal processor (not shown), a cryptoprocessor (not shown), graphics processor 616, one or more antenna 618,touch screen display 620, touch screen controller 622, other displays(such as liquid-crystal displays, cathode-ray tube displays and e-inkdisplays, not shown), battery 624, an audio codec (not shown), a videocodec (not shown), global positioning system (GPS) device 628, compass630, an accelerometer (not shown), a gyroscope (not shown), speaker 632,camera 634, and a mass storage device (such as hard disk drive, a solidstate drive, compact disc (CD), digital versatile disc (DVD)) (notshown), and so forth. In various embodiments, processor 604 may beintegrated on the same die with other components to form a System onChip (SoC).

In various embodiments, volatile memory (e.g., DRAM 608), non-volatilememory (e.g., ROM 610), flash memory 612, and the mass storage devicemay include programming instructions configured to enable computingdevice 600, in response to execution by processor(s) 604, to practiceall or selected aspects of the processes described herein. For example,one or more of the memory components such as volatile memory (e.g., DRAM608), non-volatile memory (e.g., ROM 610), flash memory 612, and themass storage device may include temporal and/or persistent copies ofinstructions that, when executed, enable computing device 600 to operatecontrol module 636 configured to practice all or selected aspects of theprocesses described herein. Memory accessible to computing device 600may include one or more storage resources that are physically part of adevice on which computing device 600 is installed and/or one or morestorage resources that is accessible by, but not necessarily a part of,computing device 600. For example, a storage resource may be accessed bycomputing device 600 over a network via communications chips 606.

Communication chips 606 may enable wired and/or wireless communicationsfor the transfer of data to and from computing device 600. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communication channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. Many of the embodiments described herein maybe used with WiFi and 3GPP/LTE communication systems. However,communication chips 606 may implement any of a number of wirelessstandards or protocols, including but not limited to IEEE 702.20,General Packet Radio Service (GPRS), Evolution Data Optimized (Ev-DO),Evolved High Speed Packet Access (HSPA+), Evolved High Speed DownlinkPacket Access (HSDPA+), Evolved High Speed Uplink Packet Access(HSUPA+), Global System for Mobile Communications (GSM), Enhanced Datarates for GSM Evolution (EDGE), Code Division Multiple Access (CDMA),Time Division Multiple Access (TDMA), Digital Enhanced CordlessTelecommunications (DECT), Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. Computing device 600 may include a plurality of communicationchips 606. For instance, a first communication chip 606 may be dedicatedto shorter range wireless communications such as Wi-Fi and Bluetooth anda second communication chip 606 may be dedicated to longer rangewireless communications such as GPS, EDGE, GPRS, CDMA, WiMAX, LTE,Ev-DO, and others.

In various implementations, computing device 600 may be a laptop, anetbook, a notebook, an ultrabook, a smart phone, a computing tablet, apersonal digital assistant, an ultra mobile PC, a mobile phone, adesktop computer, a server, a printer, a scanner, a monitor, a set-topbox, an entertainment control unit (e.g., a gaming console), a digitalcamera, a portable music player, or a digital video recorder. In furtherimplementations, computing device 600 may be any other electronic devicethat processes data.

Computer-readable media (including non-transitory computer-readablemedia), methods, systems and devices for performing the above-describedtechniques are illustrative examples of embodiments disclosed herein.Additionally, other devices may be configured to perform variousdisclosed techniques.

The following paragraphs describe examples of various embodiments. Invarious embodiments, one or more computer-readable media haveinstructions that, when executed, cause an NM apparatus to: receive afirst report, including one or more measurements taken by a first UE, inresponse to an event related to a handover of the first UE between afirst RAT and a second RAT different from the first RAT; receive asecond report including one or more measurements taken by a second UE inresponse to an event related to a handover of the second UE between thefirst RAT and a third RAT different from the first RAT; and identify ahole in a coverage area of the first RAT based at least in part on thefirst and second reports. In some embodiments, the first RAT is anE-UTRA technology. In some embodiments, each of the second and thirdRATs are an UTRA technology or a GERA technology. In some embodiments,the handover of the first UE between the first RAT and the second RAT isa handover of the first UE between a first E-UTRAN cell and the secondRAT, and the handover of the second UE between the first RAT and thethird RAT is a handover of the second UE between a second E-UTRAN celland the third RAT, the second E-UTRAN cell different from the firstE-UTRAN cell. In some embodiments, the one or more measurements includedin the first report include one or more of RSRP, RSRQ, an identifier ofa cell that served the first UE in the first RAT, location information,and a time stamp representative of a time of an event related to ahandover. In some embodiments, the first and second UEs are a common UE.In some embodiments, identify a hole in a coverage area of the first RATbased at least in part on the first and second reports includescorrelate the first and second reports. In some embodiments, the one ormore computer-readable media further have instructions that, whenexecuted, cause the NM apparatus to recommend a corrective action basedon the identified hole. Some embodiments of an NM apparatus includecombinations of the foregoing.

In various embodiments, an eNB associated with a first RAT includes:first transmitter circuitry to transmit, to a UE in a cell served by theeNB, a command to handover the UE to a second RAT that is different fromthe first RAT; receiver circuitry to receive, from the UE in response tothe command, one or more measurements taken by the UE and representativeof conditions proximate to an edge of the cell; and second transmittercircuitry to transmit, to a DM apparatus or an NM apparatus, a reportincluding the one or more measurements for use in identifying coverageholes in the first RAT. In some embodiments, the second RAT includes aUTRA technology or a GERA technology. In some embodiments, the one ormore measurements are taken by the UE in response to receiving thecommand at the UE. In some embodiments, the one or more measurements aretaken by the UE prior to receiving the command at the UE. In someembodiments, the first transmitter circuitry is further to transmit, tothe UE, parameters representative of which measurements are to be takenby the UE as representative of conditions proximate to the edge of thecell. In some embodiments, the parameters are representative of one ormore of RSRP, RSRQ, an identifier of the cell, location information, anda time stamp representative of a time of an event related to a handover.In some embodiments, transmit, to a DM apparatus or an NM apparatus, areport including the one or more measurements includes transmit thereport to a CCO function of an NM apparatus. Some embodiments of an eNBinclude combinations of the foregoing.

In various embodiments, a UE includes: receiver circuitry to receive acommand from an eNB serving the UE, the eNB associated with a first RAThaving a coverage hole proximate the UE, to handover the UE to a secondRAT different from the first RAT; transmitter circuitry to transmit tothe eNB, in response to receiving the command, one or more measurementstaken by the UE and representative of conditions proximate to thecoverage hole; and handover circuitry to perform the handover to thesecond RAT after the one or more measurements are transmitted to theeNB. In some embodiments, the second RAT is a UTRA technology or a GERAtechnology. In some embodiments, receive a command to handover the UE toa second RAT occurs when the UE is proximate to an edge of a cell of thefirst RAT served by the eNB. In some embodiments, receive a command tohandover the UE to a second RAT occurs when the UE is proximate to anedge of an E-UTRAN cell served by the eNB and no other E-UTRAN cell issufficiently close to the UE to serve the UE. In some embodiments, theUE further includes measurement circuitry to take the one or moremeasurements, the one or more measurements including one or moremeasurements of the group of measurements consisting RSRP, RSRQ, anidentifier of a cell that served the UE in the first RAT, locationinformation, and a time stamp representative of a time of an eventrelated to a handover. Some embodiments of a UE include combinations ofthe foregoing.

Although certain embodiments have been illustrated and described hereinfor purposes of description, a wide variety of alternate and/orequivalent embodiments or implementations calculated to achieve the samepurposes may be substituted for the embodiments shown and describedwithout departing from the scope of the present disclosure. Thisapplication is intended to cover any adaptations or variations of theembodiments discussed herein. Therefore, it is manifestly intended thatembodiments described herein be limited only by the claims.

Where the disclosure recites “a” or “a first” element or the equivalentthereof, such disclosure includes one or more such elements, neitherrequiring nor excluding two or more such elements. Further, ordinalindicators (e.g., first, second or third) for identified elements areused to distinguish between the elements, and do not indicate or imply arequired or limited number of such elements, nor do they indicate aparticular position or order of such elements unless otherwisespecifically stated.

1. One or more computer-readable media having instructions that, whenexecuted, cause a network management (NM) apparatus to: receive areport, including one or more measurements taken by a user equipment(UE), in response to an event related to a handover of the UE between afirst radio access technology (RAT) and a second RAT different from thefirst RAT; and identify a hole in a coverage area of the first RAT basedat least in part on the report.
 2. The one or more computer-readablemedia of claim 1, wherein the first RAT is an evolved universalterrestrial radio access (E-UTRA) technology.
 3. The one or morecomputer-readable media of claim 1, wherein the second RAT is auniversal mobile telecommunications system terrestrial radio access(UTRA) technology or a global system for mobile communications enhanceddata rates for global system for mobile communication evolution radioaccess (GERA) technology.
 4. The one or more computer-readable media ofclaim 1, wherein at least one of the one or more measurements is made atthe time of the handover of the UE between the first RAT and the secondRAT.
 5. The one or more computer-readable media of claim 1, wherein thereport comprises one or more of reference signal received power (RSRP),reference signal received quality (RSRQ), an identifier of a cell thatserved the UE in the first RAT, location information, and a time stamprepresentative of a time of the event related to the handover.
 6. Theone or more computer-readable media of claim 1, wherein the handover ofthe UE between the first RAT and the second RAT comprises a handover ofthe UE from the first RAT to the second RAT.
 7. The one or morecomputer-readable media of claim 1, wherein the UE is a smart phone. 8.The one or more computer-readable media of claim 1, further havinginstructions that, when executed, cause the NM apparatus to: recommend acorrective action based on the identified hole.
 9. An evolved nodeB(eNB) associated with a first radio access technology (RAT), the eNBcomprising: first transmitter circuitry to transmit, to a user equipment(UE) in a cell served by the eNB, a command to handover the UE to asecond RAT that is different from the first RAT; receiver circuitry toreceive, from the UE, one or more measurements taken by the UE inresponse to an event related to the handover; and second transmittercircuitry to transmit, to a management apparatus, a report including theone or more measurements for use in identifying coverage holes in thefirst RAT.
 10. The eNB of claim 9, wherein the second RAT comprises auniversal mobile telecommunications system terrestrial radio access(UTRA) technology or a global system for mobile communications enhanceddata rates for global system for mobile communications evolution radioaccess (GERA) technology.
 11. The eNB of claim 9, wherein the one ormore measurements are taken by the UE in response to receiving thecommand at the UE.
 12. The eNB of claim 9, wherein the one or moremeasurements are taken by the UE prior to receiving the command at theUE.
 13. The eNB of claim 9, wherein the first transmitter circuitry isfurther to: transmit, to the UE, parameters representative of whichmeasurements are to be taken by the UE during the event related to thehandover.
 14. The eNB of claim 13, wherein the parameters arerepresentative of one or more of reference signal received power (RSRP),reference signal received quality (RSRQ), an identifier of the cell,location information, and a time stamp representative of a time of anevent related to a handover.
 15. The eNB of claim 9, wherein transmit,to the management apparatus, a report including the one or moremeasurements comprises transmit the report to a centralized coverage andcapacity optimization (CCO) function of a network management (NM)apparatus.
 16. A user equipment (UE) comprising: receiver circuitry toreceive a command from an evolved nodeB (eNB) serving the UE, the eNBassociated with a first radio access technology (RAT), to handover theUE to a second RAT different from the first RAT; transmitter circuitryto transmit to the eNB, in response to an event related to the handover,one or more measurements taken by the UE; and handover circuitry toperform the handover to the second RAT.
 17. The UE of claim 16, whereinthe second RAT is a universal mobile telecommunications systemterrestrial radio access (UTRA) technology or a global system for mobilecommunications enhanced data rates for global system for mobilecommunication evolution radio access (GERA) technology.
 18. The UE ofclaim 16, wherein receive a command to handover the UE to a second RAToccurs when the UE is proximate to an edge of a cell of the first RATserved by the eNB.
 19. The UE of claim 18, wherein receive a command tohandover the UE to a second RAT occurs when the UE is proximate to anedge of an E-UTRAN cell served by the eNB and no other E-UTRAN cell issufficiently close to the UE to serve the UE.
 20. The UE of claim 16,further comprising: measurement circuitry to take the one or moremeasurements, the one or more measurements comprising one or moremeasurements of the group of measurements consisting of reference signalreceived power (RSRP), reference signal received quality (RSRQ), anidentifier of a cell that served the UE in the first RAT, locationinformation, and a time stamp representative of a time of an eventrelated to a handover.
 21. One or more computer-readable media havinginstructions that, when executed, cause a user equipment (UE) to:receive a command from an evolved nodeB (eNB) serving the UE, the eNBassociated with a first radio access technology (RAT), to handover theUE to a second RAT different from the first RAT; transmit to the eNB, inresponse to an event related to the handover, one or more measurementstaken by the UE; and perform the handover to the second RAT.
 22. The oneor more computer-readable media of claim 21, wherein the second RAT is auniversal mobile telecommunications system terrestrial radio access(UTRA) technology or a global system for mobile communications enhanceddata rates for global system for mobile communication evolution radioaccess (GERA) technology.
 23. The one or more computer-readable media ofclaim 21, wherein receive a command to handover the UE to a second RAToccurs when the UE is proximate to an edge of a cell of the first RATserved by the eNB.
 24. The one or more computer-readable media of claim23, wherein receive a command to handover the UE to a second RAT occurswhen the UE is proximate to an edge of an E-UTRAN cell served by the eNBand no other E-UTRAN cell is sufficiently close to the UE to serve theUE.
 25. The one or more computer-readable media of claim 21, furtherhaving instructions that, when executed, cause the UE to: take the oneor more measurements, the one or more measurements comprising one ormore measurements of the group of measurements consisting of referencesignal received power (RSRP), reference signal received quality (RSRQ),an identifier of a cell that served the UE in the first RAT, locationinformation, and a time stamp representative of a time of an eventrelated to a handover.